Borrow ETH on Compound V3

WHAT IT DOES

This tool enables you to borrow ETH on Compound V3 (Comet), the next-generation lending protocol, against USDC collateral. It reads your USDC collateral balance on Ethereum Mainnet, the Compound V3 Comet contract details, and the current gas price to provide an accurate cost estimate before you commit. The tool then calculates your available borrow capacity based on your supplied collateral, displays the current borrow APR, and submits a borrow transaction to withdraw ETH against your collateral.

Compound V3 is a streamlined lending protocol that focuses on efficiency and security, with isolated markets that reduce systemic risk. The USDC market on Compound V3 allows users to supply USDC as collateral and borrow ETH, with interest rates determined by supply and demand dynamics. Borrowing against collateral allows you to access liquidity without selling your assets, while the protocol's liquidation mechanism protects lenders.

HOW TO USE

Connect your wallet using the "connect" button. Ensure you are connected to Ethereum Mainnet (chain ID 1) — the tool will display your current chain ID, USDC collateral balance, available borrow capacity in ETH, current borrowed ETH balance, and the current borrow APR. Enter the amount of ETH you wish to borrow in the input field. The tool will display the Comet contract address and estimate the gas cost for the transaction.

Review the borrow summary, then click "borrow ETH on Compound V3" to submit the transaction through your wallet. The tool will check that you have sufficient collateral to support the borrow amount, then execute the borrow. After confirmation, the ETH will be sent to your wallet, and your borrowed balance will increase. The borrow APR accrues continuously, and you must maintain sufficient collateral to avoid liquidation.

TECHNICAL MECHANISM — COMPOUND V3 BORROW

The tool interacts with the Compound V3 Comet contract, which implements the withdraw(address asset, uint256 amount) function. For the USDC market, the withdraw function with asset = address(0) (native ETH) withdraws ETH against the user's collateral. Before executing the borrow, the tool reads the user's collateral balance using collateralBalanceOf(address) and calculates the available borrow capacity using quoteCollateral(uint256 baseAmount), which determines how much ETH can be borrowed against a given amount of USDC collateral.

The borrow APR is read using getBorrowRate(uint8) which returns the current borrow rate per second. This rate is variable and changes based on market utilization — higher utilization leads to higher rates to incentivize additional supply. The tool displays the APR as an annualized percentage for user understanding. The borrow transaction is subject to the protocol's borrowing limits and health factor requirements — if the borrow would make the position unhealthy, the transaction will revert. The protocol's liquidation mechanism ensures that lenders are protected: if the user's collateral value falls below the required threshold, the position can be liquidated by external actors.

WHAT IT CANNOT SEE

This tool cannot estimate exact gas costs without a live RPC call, and gas prices on Ethereum Mainnet may change between quoting and execution. It cannot guarantee APR rates, which fluctuate based on market conditions, supply and demand dynamics, and protocol utilization. The tool cannot verify the Comet contract address is correct beyond the pre-configured mapping, and if the mapping becomes outdated, the transaction could fail or be sent to the wrong contract. It cannot cancel a transaction once submitted, and if the transaction fails due to gas issues or contract errors, you may still pay gas fees. The tool cannot handle borrowing on non-Ethereum chains or support collateral or borrow assets other than those supported by the specific Comet market (USDC collateral, ETH borrow). It also cannot guarantee the safety of borrowed funds, as liquidation risk exists if collateral value drops.

PLEASE NOTE — ETHEREUM MAINNET ONLY

This tool works exclusively on Ethereum Mainnet (chain ID 1) with the USDC market on Compound V3. You must be connected to Ethereum Mainnet to use this tool. The tool only supports borrowing ETH against USDC collateral — it does not support other collateral types or borrow assets. The USDC market requires that you have supplied USDC as collateral before you can borrow. Borrowing increases your debt position and accrues interest automatically. If your collateral falls below the required ratio, your position may be liquidated. This tool provides a simple borrow interface; repayments are not supported and must be performed through Compound V3's official mechanisms.